What Is the Link Between BP and Neurological Disorders?

It can be surprising to hear that a skin blistering condition like bullous pemphigoid (BP) is connected to a neurological condition like Parkinson’s disease. However, research shows that BP is associated with several neurological disorders. The strongest and most consistently reported associations are with dementia and Parkinson’s disease, though links to stroke and multiple sclerosis have also been observed in some studies ^[1][2].

The connection involves the immune system and two specific proteins: BP180 and BP230. In the skin, these proteins act like anchors, holding the top layers of skin to the bottom layers ^[3]. Bullous pemphigoid is an autoimmune disease, meaning the immune system mistakenly creates antibodies (immune proteins that recognize and neutralize targets) to attack these anchors. When the immune system attacks them, the skin separates, filling with fluid and creating tense blisters ^[4].

What researchers have discovered is that related forms of these same proteins also exist in the central nervous system and brain, where they help support the structure and stability of nerve cells ^[5][6][7].

The Cross-Reactivity Hypothesis: What Researchers Are Studying

Because these proteins exist in both the skin and the nervous system, researchers have proposed a hypothesis called cross-reactivity to explain why the two conditions might be linked ^[8].

According to this proposed theory, when a person has a neurological condition, nerve cells undergo damage. This damage might expose the nervous system’s versions of the BP180 and BP230 proteins to the immune system. The immune system might then register them as foreign invaders and develop antibodies against them. As these antibodies circulate through the body, they might eventually “cross-react” with the skin’s version of the proteins, leading to blisters ^[9].

It is important to understand that this is a research hypothesis, not a proven sequence of events. There is no single proven mechanism that fully explains the link between the brain and the skin. Not every patient with these antibodies develops skin blisters, and having antibodies in the blood does not automatically mean they will cause disease ^[10][11].

What This Means For You

If you have both BP and a neurological disorder like Parkinson’s disease, it is completely normal to have questions about what this means for your health:

• Association does not equal causation: Having Parkinson’s disease does not mean it directly caused your BP, nor does having BP mean your neurological disease is worsening. The vast majority of people with Parkinson’s will never develop BP.
• The timing varies: In many cases, the neurological disorder is diagnosed first, sometimes years before the skin blisters appear ^[12][13]. However, this timeline varies widely from person to person and does not prove that the neurological condition caused the blisters.
• BP is not attacking your brain: The blisters are a skin condition. Developing BP does not mean the immune system is actively attacking your brain or central nervous system.
• Watch for signs of infection: Widespread blisters, skin erosions, or fever warrant prompt medical assessment, especially if you have mobility or immune challenges.

Is It Caused by Medications?

When a new symptom appears, it is natural to wonder if a medication is to blame. Some drugs are known to trigger bullous pemphigoid—most notably certain diabetes medications called gliptins, and some diuretics ^[14].

Standard Parkinson’s disease medications, like levodopa or carbidopa, are generally not considered established causes of BP ^[15]. Because both your underlying conditions and your medications could be playing a role, your care team should perform a complete review of your prescription drugs, over-the-counter medicines, and supplements. Do not stop taking your Parkinson’s medication or any other prescribed drugs without your doctor’s guidance.